Add specific goal to build latest only on master

[kacperkrzyzak]

What this PR does / why we need it:
Multiarch goal builds latest on every release branch, we want to build it only on master.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #
https://github.ibm.com/IBMPrivateCloud/roadmap/issues/48788

Specify your PR reviewers:

/cc @gyliu513 @horis233

Special notes for your reviewer:

[horis233]

/lgtm

[ibm-ci-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: horis233, kacperkrzyzak

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [horis233]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[ibm-ci-bot]

@kacperkrzyzak: Updated the job-config configmap in namespace default using the following files:

• key IBM.ibm-licensing-operator.master.yaml using file prow/cluster/jobs/IBM/ibm-licensing-operator/IBM.ibm-licensing-operator.master.yaml

In response to this:

What this PR does / why we need it:
Multiarch goal builds latest on every release branch, we want to build it only on master.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #
https://github.ibm.com/IBMPrivateCloud/roadmap/issues/48788

Specify your PR reviewers:

/cc @gyliu513 @horis233

Special notes for your reviewer:

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.